Reported illness

Over 16 weeks, teams from Australia, South Africa and New Zealand played in all three countries.

These findings could be relevant to the Olympics and might contribute to the home advantageProf Martin Schwellnus, Report author

For matches played on home turf, before international travel, there were 15 reported illnesses in every 1,000 days played.

In locations where players were more than five hours' time difference away from home, this rose to 33 reported illnesses in every 1,000 days played.

For matches played back home after international travel - illness fell to 11 incidents in every 1,000 days played.

Almost a third of all illnesses reported were respiratory conditions, followed by gut problems and skin and soft tissue conditions.

Home advantage

Prof Schwellnus said: "These findings could be relevant to the Olympics and might contribute to a home advantage."

Although Prof Schwellnus also pointed out that this study concentrated on a tournament played from February to May with participation every week - a different environment to the Olympic athletes who generally compete just once.

His research is now looking at which players are more prone to illness as some were more likely than others to become ill. He said: "It is a player thing, with certain people being particularly sensitive to a new environment, rather than a travel thing."

Other factors that have been shown to work in the home teams' favour are familiar surroundings and the backing of the crowd. But there are also factors that can have a negative impact like increased pressure and expectation and worries about letting people down.